blood splatter lab refection

how could blood splatters be used as evidence in a crime?
could they?

i think that blood splatters could be used to an extent in a crime but only to show where the crime happened. i don't think it could be used in a crime to see high the blood fell from because i don't think that there really is a set pattern to how the blood falls, or how high it fell from. also you need to take into account how much blood had fallen, which would make the splatter bigger no matter how high it fell from.